Date: Tue, 28 Mar 2017 18:09:02 +0000 (UTC) From: Warner Losh <imp@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: svn commit: r316100 - head/sys/boot/i386/boot2 Message-ID: <201703281809.v2SI92Ck011780@repo.freebsd.org>
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Author: imp Date: Tue Mar 28 18:09:01 2017 New Revision: 316100 URL: https://svnweb.freebsd.org/changeset/base/316100 Log: Remove -fno-guess-branch-probability and -fno-unit-at-a-time. bde enabled -fno-guess-branch-probability in 2003, well before our current compiler was imported. At the time it produced weirdly orded code. It no longer does that. It also saves 0-4 bytes depending on other options. kan disabled unit-at-a-time in 2004 because it badly mangled boot2 so it wouldn't work. That too was before the 4.2.1 compiler, where it no longer does that. This saves 44 bytes. I had planned to document why they were needed, but when I discovered their antiquity, I removed them and boot2 still works and is smaller. In qemu, the old and new boot2's behaved identically. These are gcc specific hacks, and won't affect clang-built boot2 at all. Modified: head/sys/boot/i386/boot2/Makefile Modified: head/sys/boot/i386/boot2/Makefile ============================================================================== --- head/sys/boot/i386/boot2/Makefile Tue Mar 28 17:37:49 2017 (r316099) +++ head/sys/boot/i386/boot2/Makefile Tue Mar 28 18:09:01 2017 (r316100) @@ -38,8 +38,6 @@ CFLAGS= -fomit-frame-pointer \ -Winline CFLAGS.gcc+= -Os \ - -fno-guess-branch-probability \ - -fno-unit-at-a-time \ --param max-inline-insns-single=100 .if ${COMPILER_TYPE} == "gcc" && ${COMPILER_VERSION} <= 40201 CFLAGS.gcc+= -mno-align-long-strings
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